001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 */
017package org.apache.bcel.generic;
018
019import org.apache.bcel.Const;
020import org.apache.bcel.classfile.ConstantCP;
021import org.apache.bcel.classfile.ConstantNameAndType;
022import org.apache.bcel.classfile.ConstantPool;
023import org.apache.bcel.classfile.ConstantUtf8;
024import org.apache.bcel.classfile.Utility;
025
026/**
027 * Super class for InvokeInstruction and FieldInstruction, since they have some methods in common!
028 */
029public abstract class FieldOrMethod extends CPInstruction implements LoadClass {
030
031    /**
032     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
033     */
034    FieldOrMethod() {
035        // no init
036    }
037
038    /**
039     * @param index to constant pool
040     */
041    protected FieldOrMethod(final short opcode, final int index) {
042        super(opcode, index);
043    }
044
045    /**
046     * @return name of the referenced class/interface
047     * @deprecated If the instruction references an array class, this method will return "java.lang.Object". For code
048     *             generated by Java 1.5, this answer is sometimes wrong (e.g., if the "clone()" method is called on an
049     *             array). A better idea is to use the {@link #getReferenceType(ConstantPoolGen)} method, which correctly
050     *             distinguishes between class types and array types.
051     *
052     */
053    @Deprecated
054    public String getClassName(final ConstantPoolGen cpg) {
055        final ConstantPool cp = cpg.getConstantPool();
056        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
057        final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
058        if (className.startsWith("[")) {
059            // Turn array classes into java.lang.Object.
060            return "java.lang.Object";
061        }
062        return Utility.pathToPackage(className);
063    }
064
065    /**
066     * @return type of the referenced class/interface
067     * @deprecated If the instruction references an array class, the ObjectType returned will be invalid. Use
068     *             getReferenceType() instead.
069     */
070    @Deprecated
071    public ObjectType getClassType(final ConstantPoolGen cpg) {
072        return ObjectType.getInstance(getClassName(cpg));
073    }
074
075    /**
076     * Gets the ObjectType of the method return or field.
077     *
078     * @return type of the referenced class/interface
079     * @throws ClassGenException when the field is (or method returns) an array,
080     */
081    @Override
082    public ObjectType getLoadClassType(final ConstantPoolGen cpg) {
083        final ReferenceType rt = getReferenceType(cpg);
084        if (rt instanceof ObjectType) {
085            return (ObjectType) rt;
086        }
087        if (rt instanceof ArrayType) {
088            return Type.OBJECT;
089        }
090        throw new ClassGenException(rt.getClass().getCanonicalName() + " " + rt.getSignature() + " does not represent an ObjectType");
091    }
092
093    /**
094     * @return name of referenced method/field.
095     */
096    public String getName(final ConstantPoolGen cpg) {
097        final ConstantPool cp = cpg.getConstantPool();
098        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
099        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
100        return ((ConstantUtf8) cp.getConstant(cnat.getNameIndex())).getBytes();
101    }
102
103    /**
104     * Gets the reference type representing the class, interface, or array class referenced by the instruction.
105     *
106     * @param cpg the ConstantPoolGen used to create the instruction
107     * @return an ObjectType (if the referenced class type is a class or interface), or an ArrayType (if the referenced
108     *         class type is an array class)
109     */
110    public ReferenceType getReferenceType(final ConstantPoolGen cpg) {
111        final ConstantPool cp = cpg.getConstantPool();
112        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
113        String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
114        if (className.startsWith("[")) {
115            return (ArrayType) Type.getType(className);
116        }
117        className = Utility.pathToPackage(className);
118        return ObjectType.getInstance(className);
119    }
120
121    /**
122     * @return signature of referenced method/field.
123     */
124    public String getSignature(final ConstantPoolGen cpg) {
125        final ConstantPool cp = cpg.getConstantPool();
126        final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
127        final ConstantNameAndType cnat = (ConstantNameAndType) cp.getConstant(cmr.getNameAndTypeIndex());
128        return ((ConstantUtf8) cp.getConstant(cnat.getSignatureIndex())).getBytes();
129    }
130}